WoW PvP in Vanilla was all about high end raiders beating the snot out of Dungeon Heroes. This was due to the fact PvP gear simply did not exist, at least not in its current incarnation. The BG's were dominated by players with Perdition's Blades, Askhandi's, ect...
WoW PvP in TBC shifted more towards rated Arena gear. The shift was so strong that many players PvP'd in order to get gear to raid with (due to the quality being so similar).
In Wrath they found a better balance...sorta. The players who ONLY PvP do not have a gear advantage. The players who both raid (25 mans) and PvP have the advantage. This comes due to the overpowering nature of most raid gear when balanced with PvP resilience gear. Most notably the raid aspect is noticed by Humans and their Trinket spots. In the Tournament Realm, the top teams are all Alliance Humans (some exceptions) due to the availability of PvE Trinkets along with the other PvP gear.
That being said, here is a fun video of a Mage in full PvE gear. Are we at the point of S4 in TBC with PvE Geared Rogues with Illidan's Swords? You be the judge. =)http://www.youtube.com/watch?v=_7fx1coqUuo
Combat Rogue 3v3. Full PvE geared with serious strats:http://www.youtube.com/watch?v=xOfaCN_UB_0